This invention relates to an apparatus and a method for producing thermoplastic synthetic fibers, especially fibers used for non-woven fabrics or other garments. More specifically, it relates to a compact apparatus which can produce regular fibers, composite fibers and so on, continuously throughout from the melt spinning step to final fiber obtaining step with high speed. Furthermore specifically, it relates to an apparatus equipped with a melt spinning device, a tow drawer and a tow accumulating device, a high-speed tow stretching device, and so on, being arranged functionally according to sequential time-to-time processing steps of materials, applicable for producing a tow having a large fineness such as 10,000 dtex or more, and a producing method using the said apparatus.
Generally, as apparatus for producing thermoplastic synthetic fibers, there have been two types of apparatus as roughly classified. The first is for producing continuous fibers (long fiber or filament) having a small amount of total fineness that are to be directly knitted (or woven) with a knitting machine or weaving machine, then processed into garments or the like. The second is for producing short fibers (staples) or a tow supplied as woven or non-woven fabrics produced through intermediate steps of spinning, carding, and so on.
In the case of said first apparatus for producing continuous fiber, total fineness of obtained fibers is small as 50-3000 dtex at most. As the first apparatus for producing continuous fibers, a high-speed apparatus so called xe2x80x9cSpin-Draw-Texture typexe2x80x9d is conventionally known, which spins fibers from its each spinneret, stretches the fibers at high speed, processes the fibers to be bulky, then winds the fibers on its winder. This apparatus is applicable for small fineness fibers such as previously mentioned. Accordingly, it is possible to produce continuous fibers at a high speed of 3,000-7,000 m/min. approximately. However, in the case of producing short fibers or tow using the first apparatus, it is necessary to set many paper tubes (bobbins of wound fibers) to creels after crimping process, then unwind the fibers as tows and be reprocessed. Thus it requires a widely extended area for device of creels, and it is uneconomical from the view point of operability or re-processing.
As the second type apparatus for producing short fibers or a tow, an apparatus so called xe2x80x9cShort-Spin typexe2x80x9d is conventionally known which arranges a melt spinning device equipped with a large-size spinneret in which many spinning holes are bored, a low-speed stretching device, and a stuffer type crimping processor. In the case of this Short-Spin type apparatus, unstretched fibers are spun at low speed from a large-size spinneret which approximately 3,000-50,000 spinning holes are bored, then stretched at a low speed of 30-150 m/min. to give a tow having a total fineness of approximately 500,000-2,500,000 dtex. In this apparatus, the size of the spinneret is large, and the density of the bored spinning holes is high, so that the distribution of raw resin inside the spinneret tends to be non-uniform, also the fineness of spun fibers tends to be non-uniform. Further in the case of producing composite fibers, where there is non-uniformity in the distribution for two kinds of thermo-plastic resins, it is difficult to produce fibers having a uniform composite ratio with less eccentricity.
Further, in the case of producing fibers having small fineness, that is 3 dtex or less of single fiber fineness, breakage of single fiber or melting adhesion of each single fibers tend to occur.
Also in the case such as when spun fibers are wound on a stretching device, or when fine adjustment of the crimping processor is required, it is necessary to stop the apparatus as a whole including the spinning device, so that much thread is wasted, so it has been problem on this apparatus.
There has also been another conventional possibility to produce tow having large fineness by arranging an apparatus of the so called xe2x80x9cConventional Typexe2x80x9d equipped with many relatively small spinneret blocks wherein the density of the bored spinning holes is low. However, because many spinnerets are required, the spinning block become long and large. Accordingly, it requires substantial effort to change each spinneret or check and maintain related equipment such as gear pumps for each spinneret, so that the operability of this apparatus becomes adversely effected. Further, this apparatus requires many cans for stocking unstretched tows so that a large area for operation is not required.
Japanese Patent Publication (Tokkyo Kokai Koho) Hei 7-216626 (corresponding to U.S. Pat. No. 5,411,693) discloses a Short-Spin type apparatus for producing composite fibers comprising a spinning block equipped with a large-size spinneret in which many spinning holes are bored, and a special quenching device for blowing high-speed air into the space just under the surface of the spinneret from one side. In this apparatus, the production speed is low because it is not equipped with a high-speed stretching device or high-speed crimping processor. Further, properties of each single fiber tend to become non-uniform, such as non-uniform fineness or non-uniform strength, causing localized cooling of the spinneret surface from high-speed quenching air stream. Also, the surface of the spinneret is easily cooled, so that it is difficult to keep spinability and uniform fiber properties for long periods. Furthermore, this apparatus also contains the same peculiar problem as the Sort-Spin Type as previously mentioned.
Japanese Patent Publication (Tokkyo. Kokai Koho) Hei 3-130407 (corresponding to U.S. Pat. No. 5,079,812) discloses an automatic tow exchanging apparatus for feeding a tow into a can, equipped with pairs of tow feeding rolls on the frontside and backside of the apparatus. This apparatus can make rapid exchange of the tow possible, but it is a type of feeding the tow into a can, so that it is impossible to produce the tow continuously from the spinning step, via the stretching step to the crimping step.
This invention aims to provide a fiber production apparatus, in which it is possible to produce fibers having large total fineness of approximately 10,000-440,000 dtex continuously from the melt spinning step to the final (e.g. crimping) step at high stretching speed approximately 300-6,000 m/min., and which has compact whole size. And it aims to provide a fiber production apparatus wherein the spinning block is easily checked and maintained. And it also aims to provide such apparatus having a means for stocking the tow temporarily. Further, it aims to provide a fiber production apparatus which can pass the fibers into the stretching step directly from the spinning step when the apparatus is continuously driven. Furthermore, it aims to be applicable for producing various kinds of fibers such as regular fibers or composite fibers. It further aims to solve the above mentioned problem existing in the continues Long fiber producing apparatus such as Spin-Draw-Texture type, or the short fiber producing apparatus such as Short Spin type and Conventional type.
To solve the above problem, this invention provides the following:
1. A compact in-line high-speed apparatus for producing thermoplastic synthetic fibers comprising;
a) a melt spinning device equipped with a spinning block and a tow drawer wherein the spinning block has at least one extruder, at least one spinneret block, and heating means, and the tow drawer draws fibers spun from the spinning block as a bundled tow;
b) a drawn tow accumulating device equipped with at least two tow feeding rolls and a tow accumulating conveyer, wherein the tow feeding rolls can feed the tow obtained from the tow drawer onto the tow accumulating conveyer, and the tow accumulating conveyer can accumulate the tow fed from the tow feeding rolls; and
c) a high-speed tow stretching device stretching the tow supplied from the drawn tow accumulating device at high stretching speed.
2. The compact in-line high-speed apparatus for producing thermoplastic synthetic fibers according to the above article 1, further comprising a high-speed crimping processor next to the high-speed stretching device for crimping the stretched tow at high speed.
3. The compact in-line high-speed apparatus for producing thermoplastic synthetic fibers according to the above article 1, further comprising a tow cutter for cutting the stretched tow into short fibers as final products.
4. The compact in-line high-speed apparatus for producing thermoplastic synthetic fibers according to the above article 1, further comprising a tow winder or a tow box packing device for preparing the stretched tow as a final product.
5. The compact in-line high-speed apparatus for producing thermoplastic synthetic fibers according to the above article 1, wherein the drawn tow accumulating device is further equipped with a sensor detecting the accumulation state of the tow.
6. The compact in-line high speed apparatus for producing thermoplastic synthetic fibers according to the above article 1, wherein at least one of the tow feeding rolls is a pinch roll and at least one of the tow feeding rolls has a mechanism to take off from the tow passing route.
7. The compact in-line high speed apparatus for producing thermoplastic synthetic fibers according to the above article 1, wherein the melt spinning device is equipped with at least two extruders for producing multi-component thermoplastic synthetic conjugated fibers comprising at least two components.
8. The compact in-line high speed apparatus for producing thermoplastic synthetic fibers according to the above article 1, wherein the high-speed tow stretching device is equipped with a mechanism which can stretch a tow having a total fineness of 10,000-440,000 dtex at a spinning speed of 300-6,000 m/min.
9. The compact in-line high speed apparatus for producing thermoplastic synthetic fibers according to the above article 1, wherein the spinneret blocks are for spinning composite fibers having sheath-core or side-by-side configuration.
10. A method for producing thermoplastic synthetic fibers using the compact in-line high-speed apparatus for producing thermoplastic synthetic fibers according to the above article 1, characterized in supplying the tow fed from the tow feeding rolls directly to the tow stretching device, or taking at least one of the tow feeding rolls off from the tow passing route, in the high speed stretching step.
The xe2x80x9cCompact in-line high speed apparatus for producing thermoplastic synthetic fibersxe2x80x9d defined in this invention means an apparatus for thermoplastic synthetic fiber production which is equipped with devices for each process of melt spinning, tow drawing and accumulation, high-speed stretching, and optionally high-speed crimping, tow cutting and/or tow winding, along a time-to-time sequence into one continuous line, and processing raw material resins into final product of fibers (tow), at high speed.